1. Field of the Invention
The present invention relates to a display technology, and more particularly, to a detection circuit of a display panel and a method for performing detection on the display panel by using the detection circuit.
2. Description of Prior Art
The existing display panel includes a plurality of pixel units. Each pixel unit includes a pixel main portion and a pixel sub portion. In order to solve the problem of color deviation for large-angle viewing, it is commonly configured that the brightness of the pixel main portion is higher than that of the pixel sub portion, thereby improving the display effect. The pixel main portion has a first thin film transistor and the pixel sub portion has a second thin film transistor and a third thin film transistor. A primary scan line is connected to control terminals of the first thin film transistor and the second thin film transistor. When the primary scan line is inputted with a high voltage level, the first thin film transistor and the second thin film transistor are turned on, the pixel main portion and the pixel sub portion are charged with electricity by data lines, and the charges of the pixel main portion and the pixel sub portion are equal to each other after the charging is accomplished. A secondary scan line is connected to the control terminal of the third thin film transistor. When the secondary scan line is inputted with the high voltage level, the third thin film transistor is turned on, and a part of charges of a liquid crystal capacitor of the pixel sub portion is distributed to a share capacitor such that the charges of the pixel sub portion is less than that of the pixel main portion, thereby solving the problem of color deviation for large-angle viewing.
As shown in FIG. 1, a conventional detection circuit 1 includes a first detection line 11, a second detection line 12, and pixel units 15. Each scan line corresponding to the pixel unit includes a primary scan line 13 and a secondary scan line 14. The primary scan lines of odd rows (1, 3, 5, 7) of the pixel units are connected to the first detection line 11. The primary scan lines of even rows (2, 4, 6, 8) of the pixel units are connected to the second detection line 12. Also, the primary scan line of the (n+2)th row of the pixel units is connected to the secondary scan line of the (n)th row of the pixel units. Alternatively, as shown in FIG. 2, the primary scan line of the (n+4)th row of the pixel units is connected to the secondary scan line of the (n)th row of the pixel units. Other connections in FIG. 2 are similar to FIG. 1, where n is a positive integer. The conventional detection circuit only can detect whether or not the pixel main portion and the pixel sub portion are illuminated.
However, there are ITO (a transparent conductive layer) residues existed between the share capacitor and a pixel electrode of the pixel sub portion in the manufacture. Accordingly, a short may occur between the share capacitor and the pixel electrode of the pixel sub portion, and therefore controlling the third thin film transistor is not possible. When the pixel electrode of the pixel sub portion is charged with electricity, the share capacitor is also charged such that the voltages of them are identical to each other. When the pixel electrode of the pixel sub portion is accomplished in charging, the voltages of the pixel electrode of the pixel sub portion and an upper electrode of the share capacitor are the same such that the liquid crystal capacitor of the pixel sub portion cannot share a part of charges with the share capacitor, the voltage of the pixel sub portion cannot be lowered, and the brightness of the pixel sub portion becomes abnormal. That is, the display panel is abnormal. This abnormal circumstance is more apparent particularly under low gray levels (e.g., L48 gray level). Therefore, it is necessary to detect abnormalities of the display panel. The conventional detection circuit cannot detect the abnormalities of the display panel.
Therefore, there is a need to provide a detection circuit of a display panel and a method for performing detection on the display panel by using the detection circuit, for solving the problems in conventional skills.